ALLYL ALCOHOL 109
sodium carbonate, filter, add a slight excess of nitric acid, boil a
minute, add dilute ammonia and boil until neutral, i. Aclcl
a drop of ferric chloride. A red colouration is produced,
which, on boiling, becomes turbid from the formation-of basic
ferric formate. (Compare acetic acid, p. 74.)
2. Add to the solution a few drops of a solution of silver
nitrate and warm. Metallic silver is deposited as a black powder.
3. Add to the solution a few drops of a solution of mercuric
chloride and. warm. White mercurous chloride is deposited.
4. Add concentrated sulphuric acid to a little formic acid,
solid lead formate, or other salt and heat. Carbon monoxide
is evolved, and may be lighted at the mouth of the test-tube.
(HCOO),l)b+H,SO.l^PbSO.14-2l-LO-h2CO. See Appendix..
Allyl Alcohol, CH,:CILCILOH.
Tollcns, Hcnninger, Annalen, 1870, 156, 129.
50 gnus, oxalic acid.
200 „ glycerol.
,|- „ ammonium chloride.
A mixture of the above substances is heated in a retort
(o litre) over wire-gauze with condenser and receiver.* A rapid
evolution of carbon dioxide at first occurs, and the temperature,
indicated by a thermometer dipping* into the liquid, remains for
some time stationary at about 130". As the temperature slowly
rises the evolution of gas slackens, and after a time (at about
i8oc) entirely ceases. When the temperature has reached 195°
the receiver, which contains aqueous formic acid, is changed.
At 200—210° carbon dioxide is again given off, and oily streaks
are observed to run clown the neck of the retort; at the same
time a disagreeable penetrating smell is perceptible. By gently
heating the contents of the retort, a temperature of 220—230° is
maintained for some time, and when it has finally risen to 260°
the distillation is slopped. The distillate is a mixture of allyl
alcohol and water, and there is also present allyl formate,
glycerol, and acrolein. Excess of glycerol remains in the
retort and may be used again by repeating the operation with a
smaller quantity of oxalic acid (30—40 grams) until the residue is